Issue #25220, libregrtest: Set support.use_resources in setup_tests()

* Rename setup_python() to setup_tests()
* Remove use_resources parameter of runtest()
diff --git a/Lib/test/libregrtest/setup.py b/Lib/test/libregrtest/setup.py
index a7dfa79..6a1c308 100644
--- a/Lib/test/libregrtest/setup.py
+++ b/Lib/test/libregrtest/setup.py
@@ -13,7 +13,7 @@
 from test.libregrtest.refleak import warm_caches
 
 
-def setup_python(ns):
+def setup_tests(ns):
     # Display the Python traceback on fatal errors (e.g. segfault)
     faulthandler.enable(all_threads=True)
 
@@ -91,6 +91,8 @@
                 msvcrt.CrtSetReportMode(m, msvcrt.CRTDBG_MODE_FILE)
                 msvcrt.CrtSetReportFile(m, msvcrt.CRTDBG_FILE_STDERR)
 
+    support.use_resources = ns.use_resources
+
 
 def replace_stdout():
     """Set stdout encoder error handler to backslashreplace (as stderr error